Lapping head



March l0, 1931. K. E. sUMMERS LAPPINC- HEAD Filed June 14. 1927 @y mw: )f4/m4* z s I SZP NJ Il SH MC M A 2 7 p. MMR? Mw.. K M

KENNETH E. SUMMERS, 0F WESTBORO, MASSACHUSETTS, ASSIGNOR, BY IVIESNE AS- SIGNMENTS, T0 NORTON COMPANY, OF WORCESTER, MASSACHUSETTS, A CORPORA- TION 0F MASSACHUSETTS LAPPING- HEAD .Application led June 14, 1927. Serial No. 198,829.

This invention relates to a rotatable head for lapping internal surfaces, such as collars, bushings or c linder walls.

lt is the object of my invention to provide a lapping head which may be quickly and easily contracted for insertion in the hole to be lapped, and which may be yieldinglyexpanded to perform the lapping operation. Important additional features of the invention relate to the provision of means for conveniently securing separate detachable lapping elements in a lapping head, and to means for limiting the radial expansion of said head.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

A prefered form of the inventionis shown in the drawings in which Fig. l is a side elevation of my improved la ping head; f

ig. 2 is an end view thereof; Fig. 3 -is a longitudinal sectional view,

yshowing the lapping head contracted;

Fig. 4 is a similar view showing the lapping head expanded; and l Figs. 5 and 6 are transverse sectional elevations taken along the lines 5`5 and 6-6 in Fi 1.

Reerring to the drawings, my improved lapping head comprises a rotatable cylindrical supporting member 10, having an outer circumferential recess 11, adapted to receive a pair of segmental block holders 12. Each block holder is provided with an outer recess 13 preferably having undercut end and side walls;

Lapping blocks 14 are detachably inserted 1n the recesses 13 and are held in position therein by segmental clamping rings 15 (Fig. 1 and longitudinal clamping bars 16, the rings 15`and bars 16 being secured to the supy porting member 12 by screws 18 and 19.

Each block holder 12 is provided with t studs 20 (Fig. 3), projecting inwardly through openings 21 i-n the cylindrical supporting member 10. The studs 20 prevent other than radial movement of the block holders 12. The inner ends of the studs 20 are beveled for engagement with the cam surfaces of a lap-expanding plunger 22, slidable within an axial opening 23 in the supporting member 10.

As the plunger 22 is moved to the right (as Viewed in Figs. 3 and 4) the block holders 12 are moved radially outward from the position shown inl Fig. 3 to that shown in Fig. 4. Spring rings 25 are seated in grooves in the outer faces of the block holders 12 and act to yieldingly resist the radial expansion of the lap. Lugs 12a on the ends of the holders 12 are slidable in radial grooves 10b in the supporting member 10, and assist in guiding the holders 12 in their expandingand contracting movements. l

The lap is rotated by means of a rotatable driving member 30, having a partially spherical head 31 fitting within the axial opening 23. The head 31 is provided with a stud 32, projecting radially therefrom through a longitudinal slot 34 in the adjacent portion 10a of the supporting member 10, which portion is 'also externally threaded, as indicated at 35,

adjacent the slot 34.

A sleeve 36 is loosely mounted on the threaded portion 35 and is positioned axially by locking collars 37, threaded on the portion 35 and retained in adjusted position by set screws 38. The sleeve 36 is provided with an axially extended slotted portion 39 having offset end portions 40 and 41, said slotted p0rtion'y receiving the stud 32 on the head 31 of the driving member 30.

A spring 42 is interposed between the head 31 and the adjacent end of the expanding plunger 22. When the parts are in the position shown in Figs. 1 and 3, the plunger 22 is in its withdrawn or left hand position (as viewed in Fig. 3) and the stud 32 is seated in the oHset slot portion 40 of the sleeve 36.

In order to expand the lap, the driving member 30 is pushed into the supporting member 10, as indicated in Fig. 4, compressing the spring 42 and thus causing the plunger 22 to be moved yieldingly to the right` Such movement, by engagement with the studs 20, forces the block holders radially outward and thus expands the lap.

After the driving member 30 has been thus pushed axially inward relative to the supporting member 10, the sleeve 36 may be turned to locate the stud 32 in the offset slot portion 41, thus locking the stud in the position shown in Fig. 4.

The plunger 22 is provided with an axial opening 50 (Fig. 4) and with an enlarged end recess 51. A threaded rod 52 is slidable in the opening 50 and is provided with a head 53 Vfitting within the recess 51. A worm gear 54 (Fig. 3) is mounted in a rece/ss `55-at the upper or right hand enlarged end portion 56 of the driving member 30, and said worm gear is threaded on the rod 52.

An adjusting screw or worm 57 is mounted in the end portion 56 of the driving member 30 and engages the worm gear 54. The screw 57 is provided with a head 58 by which it may be conveniently adjusted. By turning the screw 57, the rod 52 may be adjusted axially of the driving shaft 30, thus limiting the outward or expanding movement of the plunger 22 and consequently limiting the extreme diameter to which the lap may be expanded.'

The driving member 30 is connected by a universal joint 60 to a tapered shank 61, adapted to be inserted in the driving shaft or spindle by which the lapping head is rotated. By using the universal joint 60 in combination with the partially spherical head 31 of the member 30, the lapping head is permitted to center itself freely in the hole to be lapped, while at the same time it is positively rotated.

The lap-expanding plunger 22 is preferably formed with two separate cam surfaces, which enables me to use a somewhat steeper angle for expanding the lap holders. The angle is not steep enough to be reversible, however, so that the lap holders and blocks while expanded yieldingly, positively resist contraction. This feature greatly assists in producing true cylindrical holes. The simultaneous expansion of both ends of the lap holders also contributes to the same result.

If the lapping blocks 14 become worn or unduly reduced in size, there may be readily removed and replaced by new blocks by simply taking out the clamping rings 15 and the holding bars 16. The lap-'expanding pressure may be adjusted by usingthe nuts 37 to move the sleeve 36 axially on the supporting body 10, and the outward expansion of the lapping blocks may be limited by axial adjustment of the headed rod 52.

Having thus described my invention and the advantages thereof, I do not wish to beA limited to the details herein disclosed otherwise than as set forth in the lclaims, but what I claim is h 1. A rotatable lapping head comprising segmental lapping members, a support therefor, means to separate said members effective to retain said head against collapse, and

means within said support and slidable relative to said separating means, comprising a rod extending longitudinally through the separating means and engageable therewith, to limit the separation of said members.

2. A lrotatable lapping head comprising segmental lapping members, a support therefor, means to separate'said members effective to retain said head against collapse, a manual device effective to render said separating means operative, and means within said .support and slidable relative to said separating means, comprising a rod extending longitudinally through the separating means and engageab'le therewith to limit the separation of said members:

3. A lapping head comprising a rotatable supporting member, a pair of segmental block holders mounted for outward movement, each in a direction perpendicular to the axis of rotation of said supporting member, yielding means'to move said holders outward, effective to retain said head against collapse, additional yielding means to move said holders inward, and means within said support and slidable relative to said yielding means for limiting the separation of said,members, comprising a rod extending longitudinally through the yielding means and having a limiting abutment engageable therewith.

4. A lapping head comprising a rotatable supporting member, a pair of segmental block holders mounted for outward movement, each in a direction perpendicular to the axis of rotation of said supporting member, yieldsupporting member, lapping elements mounted for substantially radial movement on said supporting member, a driving member slidable axially relative to said member, and a lap-expanding device slidable in said suplport, said. device being rendered operative and inoperative by the sliding movement of said driving member relative to said supporting member. y

6. A lapping headv comprising a rotatable supporting member, lapping elements mounted for. substantially radial movement on said rsupporting member,^a driving member slidable axially relative to said member, alapexpandingl device rendered operative and inoperative by'such sliding movement of said driving. member relative lto said supporting member, and manual means to lock said.-

ative to said supporting member.

' 7. A rotatable lapping head comprising segmental lapping members, a support therefor, means to separate said members and re- ".tain said head against collapse, and means to limit such separation, said limiting means compromisin a headed rod extending axially through sai separating means, the head thereof being engageable with said separating means, and means to adjust said rod axially.

8. A rotatable lapping head comprising segmental lapping members,'means to separate said members eii'ective to retain said'head j against collapse, and means to limitsuch separation, said limiting means comprising a headed rod extending longitudinally through said separating means, the head thereof being engageable vwith said separating means, a worm gear; threaded on said rod, and manual means to rotate said worm gear.

9. A- lapping head comprising a rotatable supporting member, outwardly movable lapping elements mounted thereon, an axially movable lap-expanding device yeiective to retain said head against collapse, and means comprising a rod extending longitudinally through said device and slidable relative thereto to limit the separation of said elements, and a locking sleeve eifective to hold said lap-expanding device in operative or inoperative positions at any point between its limits o movement.

10. A lapping head comprising a rotatable supporting member, outwardly movable lapping elements mounted thereon, an axiallyv movable lap-expanding device eiective to retain said head against collapse, and means comprising a rod extending longitudinally through said device and slidable relative thereto to limit the separation of said elements, a locking sleeve Yeective to hold said lap-expanding device in operative or inoperative positions at any point between its limits of movement, and means to adjust said sleeve axially to vary the expanding pressure on said lapping elements.

` 1l. A lapping head comprising a rotatable supporting member, lapping elements mounted for substantially radial movement on said supporting member, a driving member slidable axially relative to said member, and a lap-expanding device slidable in said support, said device being rendered operative and inoperative by such sliding movement oit said driving member relative to said supporting member, said lap-expanding device having axially-spaced duplicate cam surfaces engaging axially-spaced inwardly ,project- Y' ing studs associated with said lapping .ele-

ments, and effectivel to retain said head against collapse, and means comprising a rod `extending longitudinally through said device and slidable relative thereto to limit the separation of said elements.

12. A rotatable lapping head comprising segmental lapping members, a support therefor, an extension on said support, yielding means to separate said members mounted Within said extension, and means to limit such separation, said limiting means comprising a headed rod extending axially through said separating means, and means to adjust said rod axially.

13. A rotatable lapping head comprising segmental lapping members, a support therefor, an extension on said support, yielding means to separate said members mounted Within said extension, means to limit such separation, said limiting means comprising a headed rod extending axially through said separating means, and means to adjust said rod axia ly, comprising a worm gear threaded on said rod and manual means to rotate said gear.

14. A rotatable lapping head comprising segmental lapping members, a support therefor, an extension `on said support, yielding means to separate said members mounted within said extension. and slidable relative thereto, driving means for said head extending partially into said extension and movable relative thereto, means to limit separation of the members comprising a headed rod extending axially through said separating means, means to adjust said rod axially, and

' means to lock said driving member in operative or inoperative position relative to said 'supporting member, said adjusting means and said locking means being mounted at the same end of the lapping head.

15. A rotatable lapping head comprising segmental lapping members, a support therefor, means to separate said members effective to retain said headagainst collapse, yielding means to actuate said separating members, and means within said support and slidable relative to said separating means comprising a rod extending longitudinally through the separating means and engageable therewith to limit the separation of said members.

16. A rotatable lapping head comprising segmental lapping members, a support therefor, means to separate said members eective 'to retain said head against collapse, yielding means to actuate said separating members, means within said support and slidable relative to said separating means comprising a rod extending longitudinally through the separating means and engageable therewith to limit the separation of said members, and means to adjust the pressure of the yielding means relative to the separating means.

ln testimony whereof l have hereunto ajxed my signature.

MNNETH E. SRS. 

